1. Field of the Invention
The invention relates to a friction clutch, especially for motor vehicles, with a carrier plate that interacts with a pre-damper and has friction linings and acts on a flywheel, especially a dual-weight flywheel. The flywheel is connected to a crank shaft of an internal combustion engine. The pre-damper has a cover disk and an intermediate disk.
2. Description of the Prior Art
A friction clutch of this type that interacts with a dual-weight flywheel is known, for example, from German reference DE 84 10 765 U1. In this case, the dual-weight flywheel and the carrier plate are each associated with a pre-damper. The pre-damper that interacts with the flywheel is responsible for damping the vibrations created by the inevitably unsmooth running of an internal combustion engine being operated with low torque, e.g., with the transmission in neutral. In this operational mode, the residual moment that reaches the hub of the clutch is very slight. As a result, movements transmitted from the side disks to the main damper of the flywheel cannot be damped by the main damper, because the spring forces of the main damper exceed the forces of the generated vibrations. The latter forces are initially passed from the side disks to the pre-damper and damped by means of springs with a lower spring force. Should the torque increase, the pre-damper will be connected securely to the hub disk in the rotational direction, and vibrations that then occur will be damped by the main damper.
The pre-damper, interacting with the carrier plate, eliminates the residual idle noises that occasionally occur depending on the strength of clutch engagement, especially in the case of dual-weight flywheels, and cannot be adequately damped by the dual-weight flywheel.
In the known friction clutch, the pre-damper is seated on the hub and is connected via the hub to the carrier plate. The known pre-damper has a hub disk (also called the intermediate disk) securely arranged on the inner hub. Arranged on both sides of the hub disk are cover disks, which are securely connected to each other. The inner cover disk, which faces the carrier plate, is connected securely to the outer hub. The cover disks as well as the carrier plate have apertures, in which torsion springs are disposed so as to be evenly distributed circumferentially. These torsion springs usually have a very low spring rate.
The pre-damper, because it is arranged behind the clutch carrier plate, enlarges the structural length of the clutch. The growth in vehicle optimization and the simultaneous increase in equipment variety of modem vehicles makes it necessary for all components to be as compact and short in structure as possible, so that they can be housed in the engine compartment, which is becoming smaller. Furthermore, to remain competitive, manufacturers must reduce part diversity and keep the number of individual parts low.